#myVideo {
position: absolute;
object-fit: cover;
width: 100vw;
height: 100vh;
top: 0;
left: 0;
}
.show-lg{
display: block;
}
.show-md,
.show-sm{
display: none;
} @media only screen and (max-width: 1024px) {
.show-md{
display: block;
}
.show-lg,
.show-sm{
display: none;
}            
} @media only screen and (max-width: 767px) {
.show-sm{
display: block;
}
.show-lg,
.show-md{
display: none;
}  
}